SERVICER ADVANCE INVESTMENTS - Schedule of Interest Income Related to Investments in Servicer Advances (Details) - Servicer Advance Investments - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Schedule of Equity Method Investments [Line Items]
Interest income, gross of amounts attributable to servicer compensation	$ 3,544	$ 27,905	$ 17,505	$ 17,655
Amounts attributable to base servicer compensation	(590)	(2,504)	(1,746)	(1,622)
Amounts attributable to incentive servicer compensation	(3,043)	(5,230)	(9,036)	(13,951)
Interest income (expense) from servicer advance investments	$ (89)	$ 20,171	$ 6,723	$ 2,082